Pulverizing mills are well known and commonly used to reduce particle size of wet or dry food substances, chemicals, plastics and pharmaceutical products. These mills are typically constructed for use in either batch or continuous operation. An example of one type of pulverizing mill is disclosed in commonlyowned U.S. Pat. No. 4,651,934, of which applicant is a coinventor and which is incorporated by reference herein.
In breaking down bulk products into smaller particles, it is desirable to maintain consistent and repeatable machine operating conditions so as to achieve a consistent particle size. Furthermore, particularly for foods and pharmaceuticals, it is necessary that the operation be validated so that the product can be approved by the U.S. Food and Drug Administration (FDA).
Mills, such as that disclosed in applicant's prior patent, generally include a rotor with a plurality of blades rotatably mounted within a housing. Different particle sizes can be obtained by varying the product feed rate, the rotor speed, the that disclosed in U.S. Pat. No. 3,184,172 have the flexibility to change these parameters. However, in these prior art mills, there has not been a way to validate the operation of the machine, since the machine is manually operated. Such manual operation of the mill leads to inherent mistakes, such as an incorrect screen, blade, rotor speed, or feed rate.
Accordingly, it is a primary objective of the present invention to provide a system for controlling the operation of a pulverizing mill.
A further objective of the present invention is the provision of a method and means for validating the mill operation.
Another objective of the present invention is the provision of control circuitry for validating the mill operation.
Yet another objective of the present invention is the provision of a pulverizing mill control system that automatically checks the initial set-up of the mill, including such parameters as screen size, and blade shape, and sets rotor speed and feed rate.
Another objective of the present invention is the provision of a pulverizing mill with a control system that can be locally programmed or operated through a central computer or microprocessor.
These and other objectives will become apparent from the following description of the invention.